Packaging apparatus



March 3, 1970 L. M. REID rr A; 3.49

PACKAGING APPARATUS Filed Aug. 28. 1967 s Sheets-Sheet 1 L. M. REID ET PACKAGING APPARATUS March 3, 1970 Filed Aug. 28. 1967 5 Sheets-Sheet 2 FIG. 2

L. M. REID ET L mckmme APPARATUS March 3, 1970 Filed Aug. 28, 1967 5 Shee ts-Sheet 4,

March 3, 1970 Filed Aug. 28, 1967 1 FIG.1O

M. REID EHMQ PACKAGiNG APPARATUS 5 Sheets-Sheet 5 United States Patent O U.S. Cl. 53-182 18 Claims ABSTRACT OF THE DISCLOSURE A packaging machine in which a center-folded web of flexible heat-scalable sheet plastic material is intermittently fed forward in increments equal to twice the package length interval, with a dwell between successive feed cycles, the web having its center fold at the bottom, thereby being of trough formation. The web first traverses a loading station and then a sealing station. During each dwell, two articles are dropped into the center-folded web, one behind the other, spaced one package length interval with a gap therebetween. Also during each dwell, two packages are simultaneously sealed and segmented at the sealing station by a pair of F-shaped sealing jaw members.

BACKGROUND OF THE INVENTION This invention involves an improvement on the packaging machine shown in the coassigned McKay et al. US. Patent 3,331,185 issued July 18, 1967, entitled Wrapping Machine. The machine shown in said patent generally comprises means for intermittently feeding forward in single package length increments a center-folded web of flexible heat-sealable sheet plastic material with the center-folded web positioned vertically and with its center fold at the bottom, so that the web is of trough form. The center-folded web is led through a loading station and thence to a sealing station. It dwells for an interval between successive feed cycles. During each dwell, an article is dropped into the web at the loading station, and sealing means, in the form of an inverted L, as the sealing station closes on the web to form a trailing end seal across the web between the leading article in the web and the article at the loading station and a top seal. Machines such as shown in said US. Patent 3,331,185 have been fully satisfactory for many purposes, but for some purposes operate at a lower production rate than is desired.

SUMMARY OF THE INVENTION Among the several objects of the invention may be noted the provision of an improvement on the machine shown in said US. Patent 3,331,185 for increasing the production rate thereof by effecting sealing of two packages during each dwell of the web rather than one, thereby doubling the production rate per cycle. For example, where the machine shown in said patent has an operating rate of forty cycles per minute and hence forty packages per minute, the improved machine may have an operating rate of thirty-five cycles per minute and seventy packages per minute (two packages per cycle).

In general, this is attained by intermittently feeding the center-folded Web forward in increments equal to twice the package length interval, two articles to be packaged being dropped into the web at the loading station during each dwell, and by providing sealing means which functions during each dwell to form two'packages and segment these two packages from each other and from the web, by forming a top seal for two packages at the leading end of the web, by severing the web on a first transverse line trailing the leading end by one package length interval and sealing the opposed walls of the web together on both sides of this line thereby to form a 3,498,023 Patented Mar. 3, 1970 trailing transverse seal for the first package and a leading transverse seal for the second package, and by simultaneously severing the web on a second transverse line trailing the first transverse line one package length interval and sealing the opposed walls of the web together on both sides of said second transverse line thereby to form a trailing transverse seal for the second package and a leading transverse seal for the next package. Other objects and features will be in part apparent and in part pointed out hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective showing a machine of the general type disclosed in said US. Patent 3,331,185 equipped with means of this invention for simultaneously sealing and segmenting two packages per cycle;

FIG. 2 is a perspective of the sealing and segmenting means; I

FIG. 3 is forward end elevation of the sealing and segmenting means;

FIG. 4 is a fragment of FIG. 3 with parts broken away and shown in section;

FIG. 5 is an enlarged section on line 55 of FIG. 4;

FIG. 6 is a section on line 66 of FIG. 5;

FIG. 7 is a view in elevation of a hot-wire sealing jaw member per se;

FIG. 8 is an enlarged plan of the sealing and segmenting means, broken away to reduce the length of the view and with parts shown in section;

FIG. 9 is a section on line 9-9 of FIG. 8;

FIG. 10 is a view in elevation of a back-up jaw member per se; and

FIG. 11 is a wiring diagram.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, a packaging machine which has the present invention incorporated therein is shown in FIG. 1 generally to comprise a base 1 having at one end thereof, referred to as its rearward end, means 3 for supporting a roll R of a web W of flexible heat-sealable sheet plastic material, e.g., polyvinyl chloride film. These correspond to the base and roll holder indicated at 32 and 34 in said US. Patent 3,331,185. The web is unwound from the roll and is fed through a center-folding unit generally indicated at 5 (corresponding to assembly 36 shown in said patent) in which the web is center-folded with the folded web positioned vertically with its center fold at the bottom, thereby being of trough formation, open at the top. The center-folded web, designated W1, then passes forward through a loading zone or station 7. Forward of the loading station is a web feed unit 9 (corresponding to that indicated at 40 in said patent) for intermittently feeding the web forward with a dwell between successive feed cycles. This web feed unit 9 comprises a pair of endless chains 11 (corresponding to chains 184 and 188 shown in said patent) having opposed inner reaches which grip the top margin of the center-folded web and which are intermittently driven for effecting the intermittent forward feed of the web. At the loading station 7, on each cycle of the machine, two articles A (generally of square outline and relatively thin in profile) are dropped into the center-folded web between the opposed side walls 13 of the web, one article spaced behind the other one package length increment, with a gap between the articles. The center fold of the web, at which the opposed walls of the web are joined, is indicated at 15. The opposed walls 13 of the web pass on the outside of spacer plates 17 at the loading station for holding the side walls apart for loading. Fleece rollers 19 such as shown in said patent or other suitable means may be provided for engagement with the outside of the side walls of the web.

Extending vertically upward from the base adjacent its forward end are two tubular rock shafts constituted by sleeves 21 and 23. These correspond to sleeves 412 and 206 shown in said patent. Extending through these tubular rock shafts 21 and 23 are chain drive shafts 25 and 27 which, at their upper ends, carry drive sprockets for the chains 11. These chain drive shafts 25 and 27 correspond to shafts 362 and 354 shown in said patent. Shafts 25 and 27 are intermittently driven by adjustable drive mechanism housed in the base 1 for intermittently feeding the web forward. Full details of this mechanism may be ascertained from said patent. Shafts 21 and 23 are oscillated by cam mechanism housed in the base 1 during each dwell of the shafts 25 and 27 and the chains 11 for effecting sealing of the web. Full details of this cam mechanism may be ascertained from said patent.

In carrying out this invention, the mechanism for intermittently driving the shafts 25 and 27 and the chains 11 is adjusted for effecting intermittent forward feed of the web in increments corresponding to twice the desired package length. The sealing means indicated at 42 in said patent is replaced by sealing means of this invention, designated in its entirety by the reference numeral 29. This sealing means is located below chains 11 and comprises a hot-wire sealing jaw assembly 31 mounted on shaft 21 and a back-up sealing jaw assembly 33 mounted on shaft 23, these jaw assemblies being movable toward and away from one another via the oscillation of shafts 21 and 23.

The hot-wire sealing jaw assembly comprises a jaw member 35 constituted by a horizontal bar 37 having a length at least equal to twice the maximum package length interval extending forward from shaft 21, a transverse bar 39 extending vertically downward from bar 37 at its rearward end, and a second transverse bar 41 extending vertically downward from bar 37 spaced one package length interval forward of transverse sealing bar 39. Thus, jaw member 35 is in the shape of an F turned 90. Each of bars 39 and 41 has a length somewhat greater than the height of the center-folded web.

The horizontal bar 37 is a metal bar having electrical insulation facing 43 on its face toward the web (referred to as the inside face). An electrical resistance heating wire 45 extends lengthwise of bar 37 on its insulation facing. The rearward end of the wire 45 is secured to the bar 37 as indicated at 47. The forward end of the wire is secured to a wire-tensioning means 49 comprising a wire-tensioning stud 51 slidable in a block 53 at the forward end of bar 37 and biased forward to tension the wire by a spring 55 reacting from the block against a nut 56 threaded on the stud. This keeps wire 45 straight. Each of the transverse bars 39 and 41 is a metal bar welded at its upper end to bar 37 to form a rigid F-shaped assembly, and having a similar electrical insulation facing 43 on its inside face. An electrical resistance wire 57 extends lengthwise of bar 39 on its insulation facing, and a similar wire 59 extends lengthwise of bar 41 on its insulation facing. Wire 57 has its upper end fixed to bar 37 and in electrical connection with wire 45, forming a right angle corner therewith at 47. Wire 57 may be a continuation of wire 45. Similarly, wire 59 has its upper end fixed to bar 37 and in electrical contact by wire 45. Wires 57 and 59 have their lower end connected to wire-tensioning means 61 and 63 at the lower ends of bars 39 and 41 identical to the wire-tensioning means 49. These keep wires 57 and 59 straight.

The F-shaped assembly of bars 37, 39 and 41 is removably secured to an F-shaped frame generally designated 65 which in turn is secured to upper and lower extension arms 67 and 69 extending forward from shaft 21. The frame 65 comprises an upper horizontal bar 71 and bars 73 and 75 extending vertically downward from bar 71. Bar 71 has inwardly extending projections 77 and 79 at its forward and rearward ends, and each of bars 73 and 75 has an inwardly extending projection 81 at its lower end. Bar 37 is removably secured at its forward and rearward ends to projections 79 and 77, and bars 39 and 41 are removably secured at their lower ends to projections 81. Extension arms 67 and 69 are tubular, and have their rearward ends adjustably telescoped and secured to upper and lower radial arms 83 and 85 on shaft 21 (see FIG. 2). Frame 65 is secured to arms 67 and 69 as indicated at 87.

A channel member 89 straddles the bar 37, its open side facing inward. Similar channel members 91 and 93 straddle bars 39 and 41, their open sides facing inward. Studs 95 extend outward from bars 37, 39 and 41 through holes 97 in the webs 99 of channels 89, 91 and 93, these studs having heads 101 at their outer ends. Springs 103 react from these heads against the webs 99 of the channels to bias the channels inward relative to the bars 37, 39 and 41 to an extended position relative to these bars wherein the flanges 104 of the channels project inward beyond the wires 45, 57 and 59. The channels function as strippers, as will appear.

Securement of the forward end of bar 37 to projection 79. of bar 71 of frame 65 and of the lower ends of bars 39 and 41 to the projections 81 at the lower ends of bars 73 and 75 of frame 65 is effected by having tongues 105 at the forward end of bar 37 and at the lower ends of bars 39 and 41 received in grooves 107 in the projections 79 and 81, and by providing screws 109 for holding the tongues in the grooves.

The back-up sealing jaw assembly 33 comprises a jaw member 111 constituted by a horizontal bar 113 for backing'up bar 37 having a length corresponding to the length of the latter, and transverse bars 115 and 117 extending vertically downward from bar 113 for backing up bars 39 and 41. Thus, jaw assembly is in the form of an F corresponding to jaw member 35. These back-up bars have a relatively soft rubber facing 119 which may be covered with tape 121 of non-stick character, such as Teflon tape. The F-shaped assembly of back-up bars 113, 115 and 117 is removably secured to upper and lower extension arms 123 and 125 extending forward from shaft 23, these arms being tubular and having their rearward ends telescoped on and secured to upper and lower radial arms 127 and 129 on shaft 23 (see FIG. 2). This securement is by means of studs 131 projecting from arms 123 and 125 into holes 133 in bars 113, 115 and 117, the latter carrying slidable forked clips 135 for clipping into peripheral grooves 137 in the studs.

FIG. 11 shows a circuit for obtaining equalized heating of the horizontal sealing wire 45 and the two lengths of vertical sealing wires 57 and 59 of the F-shaped sealing wire arrangement. At 139 is indicated a transformer having a primary 141 and two secondaries 143 and 145 of equipotential output, e.g., 18 volts. Thus each is shown as having a 0-volt and an l8-volt tap. The sealing wires are indicated as resistances. The juncture of wires 45 and 59 is indicated at 147. This juncture 147 constitutes a point of intersection spaced from the ends of wire 45 and corresponds to a point of intersection of lines of sealing. It will be observed that the horizontal wire 45 is in effect divided at this point of intersection or juncture into two equal resistances 45a and 45b. As shown in FIG. 11, a line 149 interconnects the O-volt tap of secondary 143 and the forward end of wire 45. A line 151 interconnects the lower end of wire 57 and the 18-volt tap of secondary 145. A line 153 interconnects the O-volt tap of secondary 145 and the upper end of wire 59 (at juncture 147). A line 155 interconnects the lower end of wire 59 and the 18-volt tap of secondary 145. The result is a series loop circuit connection of wires 45, 57 and 59 with windings 143 and 145 which insures an equal or identical current flow through each of the wire lengths and thus equal heating of the wires.

Operation is as follows:

On each dwell of the center-folded web W1, shafts 21 and 23 are rocked in the direction to effect closing of the F-shaped hot-wire jaw member 35 and the F-shaped backup jaw member 111 on the web. As these jaw members close, the channels 89, 91 and 93 are forced back against the bias of springs 103 to expose the equally heated hot wires 45, 57 and 59 on jaw member 35 contacting the web, backed up by the resilient facing 119 on the back-up jaw member 111. The long horizontal wire 45 forms a top seal for the two leading packages at the leading (forward) end of the web. The wire 59 (which presses on the center-folded web in the gap between the leading (first) package and the next (second) package) effects severing of the web on a first transverse line trailing the leading end of the web by one package length interval and sealing together of the opposed walls of the web on both sides of this line, thereby to form a trailing transverse seal for the first package and a leading transverse seal for the second package. The first package will already have a leading transverse seal at the forward end of the web as a result of the previous cycle. The wire 57 (which presses on the web in the gap between the second and the third package) effects severing of the web on a second transverse line trailing the wire 59 and the first trans verse line one package length interval and sealing together of the opposed walls of the web on both sides of this line, thereby to form a trailing transverse seal for the second package and a leading transverse seal for the next package.

The shafts 21 and 23 then rock back to effect opening of jaw members 35 and 111. During the initial phase of the opening movement of these jaw members, the channels 89, 91 and 93, sliding relative tobars 37, 39 and 41 under the bias of springs 103, hold the web clamped while the wires 45, 57 and 59 back off away from the web, thus acting as strippers to prevent the web from being pulled back by the wires until the seals have had time to cool sufiiciently not to stick to the wires. On opening of the jaw members, shafts 25 and 27 are actuated to drive the chains 11 for feeding forward the web two package lengths, and, during the ensuing dwell, the jaw members are closed to form the next two packages, and so on.

In order to insure equal heating along the lengths of these electrical resistance heater wires 45, 57 and 59 and thus avoid variations in temperature therealong, the current should be identical in all wires. Connecting these wire lengths in series insures this equal current, but Where two wires must intersect to form a sharp intersecting line of sealing, there will normally be a difference in electrical potential along the lengths of the wires in a series circuit. To electrically insulate the Wires at this point of intersection would require spacing or electrical insulation and thus it would appear that there could be no single point of intersection and still maintain the normal series circuit relationship. However, in accordance with the present invention the series connection of the wire lengths and the resultant equal current flow are accomplished and a single point of intersection is attained by connecting the wires in a power supply circuit which establishes an electrical potential at the point of intersection 147 on wire 45 that is equal to the electrical potential at a point on wire 59 which lies at intersection 147. This advantageous result is obtained by interconnecting wire length 59 between the secondary tap 18 of winding 143 and the secondary tap of winding 145, the other wire lengths 45 and 57 being series connected between the remaining secondary winding taps. Thus current flowing through any resistance wire must be identical to that flowing through another. As each of the resistances 45a, 45b, 57 and 59 is equal, there is an equal voltage drop across each, the total of these four voltage drops equaling the sum of the two equal secondary winding output voltages. As the voltage drop through one resistance 4511 must equal the voltage drop across equal resistance 59 and each of these resistances is connected to the end taps of secondary 143 which supplies one half of the total potential across the four resistances, the potential at the intersection point 147 of wire 45 is equal to the potential at point 147 at the tap of resistance Wire 59. Thus these two points may be made physically and electrically common without disturbing the series current relationship. Therefore, although the secondary windings 143 and 145 are connected in a series loop circuit with resistances 45, 57 and 59, wire 45 being connected effectively across two secondary taps (tap 0 of 143 and 18 of 145) has a potential difference established thereacross so that the potential at point 147 on wire 45 is identical to the intermediate potential (relative to these two taps) present at tap 0 of winding 145, i.e., the top or point 147 of resistance 59.

As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. Packaging apparatus comprising means for intermittently feeding forward a continuous length of flexible heat-sealable sheet plastic packaging material having two opposed walls joined along one longitudinal margin of the material and open along the other longitudinal margin, with articles between said walls spaced at package length intervals and with spaces between successive packages, said feed means intermittently feeding the material forward in increments equal to twice the package length interval, and with a dwell between successive feed cycles, said walls extending beyond said articles at said open longitudinal margin, and means operative during each dwell for sealing the walls together along a line extending longitudinally of the material adjacent said other margin of the material a distance corresponding to two package length intervals, thereby to form longitudinal seals for a first package at the leading end of the material and for a second package trailing the first package, and for severing the walls on a first transverse line extending across the material trailing the leading end by one package length interval and sealing the walls on both sides of said first transverse line thereby to form a trailing transverse seal for the first package and a leading transverse seal for the second package, and for severing the walls on a second transverse line extending across the material trailing the first transverse line one package length interval and sealing the walls on both sides of said second transverse line thereby to form a trailing transverse seal for the second package and a leading transverse seal for the next package.

2. Packaging apparatus as set forth in claim 1 wherein said means for forming said seals comprises a pair of sealing jaws each comprising a longitudinal bar extending in the direction of web feed for forming the longitudinal seals for said first and second packages and two transverse bars extending from the longitudinal bar transversely to the direction of web feed and spaced a distance corresponding to one package length for severing said walls on said transverse lines and sealing them on both sides of said transverse lines, said jaws being relatively movable toward and away from one another.

3. Packaging apparatus as set forth in claim 2 wherein each of said jaws is in the shape of an F.

4. Packaging apparatus as set forth in claim 3 wherein one of said jaws has an electrical resistance wire extending lengthwise on the face of each of the longitudinal and transverse bars thereof.

5. Packaging apparatus as set forth in claim 4 wherein the wire on the longitudinal bar of said one jaw has one end secured to said one jaw and its other end secured to wire-tensioning means carried by said longitudinal bar of said one jaw, and the wire on each transverse bar of said one jaw has one end secured thereto in electrical connection with the wire on the longitudinal bar of said one jaw and its other end secured to wire-tensioning means carried by the transverse bar at its free end.

6. Packaging apparatus as set forth in claim 4 having spring-biased stripping means on the longitudinal bar and transverse bars of said one jaw.

7. Packaging apparatus as set forth in claim 4 wherein the other jaw has a resilient facing on the longitudinal bar and each of the transverse bars thereof.

8. Packaging apparatus as set forth in claim 4 wherein the wires on the transverse bars form right-angle corners with the wire on the longitudinal bar, and the wires are interconnected in a power supply circuit for effecting equal heating of the wires.

9. Packaging apparatus as set forth in claim 8 wherein the power supply circuit includes a transformer having a pair of secondary windings, said wires being series connected in a loop circuit with said windings.

10. Packaging apparatus comprising a pair of vertical rock shafts, means for intermittently feeding forward a center-folded web of flexible heat-sealable sheet plastic material between said shafts with the web arranged vertically and with its center fold at the bottom, said web having articles to be packaged inserted therein spaced at package length intervals, said web feeding being located forward of said rock shafts in the direction of web feed and being adapted to grip the top of the web and intermittently to feed the web forward in increments equal to twice the package length interval, with a dwell between successive feed cycles, a first support meansextending forward from one of said rock shafts below said feeding means, an F-shaped sealing jaw member carried by said first support means comprising a horizontal top seal bar having a length at least equal to twice the package length interval, a rearward transverse seal bar extending down from the horizontal bar at its rearward end and a forward transverse seal bar extending down from the horizontal bar spaced forward of the rearward transverse seal bar one package length interval, a second support means extending forward from the other rock shaft below said feeding means, and an F-shaped back-up jaw member carried by said second supporting means comprising a top backup bar opposite said horizontal top seal bar having a length corresponding to that of said horizontal top seal bar, and rearward and forward transverse back-up bars extending down from the horizontal back-up bar opposite the rearward and forward transverse seal bars.

11. Packaging apparatus as set forth in claim 10 wherein each of said bars of said F-shaped sealing jaw member has an electrical resistance wire extending lengthwise thereof on its face opposed to an F-shaped back-up jaw member.

12. Packaging apparatus as set forth in claim 11 wherein the wire on the horizontal bar of the F-shaped sealing jaw member has its rearward end secured to this bar and its forward end secured to wire-tensioning means at the forward end of this bar, and the wire on each transverse bar of the F-shaped sealing jaw member has its upper end fixed to the horizontal bar and in electrical connection with the wire on the latter and its lower end secured to wire-tensioning means at the lower end of the transverse bar.

13. Packaging apparatus as set forth in claim 11 having channelsstraddling the horizontal and transverse bars of the F-shaped sealing jaw member with the open sides of the channels facing the back-up jaw member, and spring means biasing these channels so that their flanges normally project beyond the wires.

14. Packaging apparatus as set forth in claim 11 wherein'the back-up jaw member has a resilient facing; on the horizontal and transverse bars thereof, and has a quick-detachable connection with said second supporting means.

15. Packaging apparatus as set forth in claim 11 wherein the wires on the transverse bars of the F-shaped. sealing jaw member form right-angle corners with the wire on the longitudinal bar, and the wires are interconnected in a power supply circuit for effecting equal heating of the wires.

16. Packaging apparatus as set forth in claim 15 wherein the power supply circuit includes a transformer having a pair of secondary windings, said wires being series connected in a loop circuit with said windings.

17. In apparatus for heat sealing plastic sheet material in which lines of sealing must intersect; a member movable against the surface of said material, said member carrying a plurality of lengths of electrical resistance wires arranged in a pattern corresponding to the lines of sealing, one of said wire lengths having at least one point space-d from the ends thereof which constitutes a point of intersection of lines of sealing, a source of electrical power, a circuit interconnecting said wire lengths to said power source to maintain a substantially equal current through all wire lengths, said wires being interconnected in said circuit to establish an electrical potential at said point of intersection on said one wire length which potential is substantially equal to the electrical potential at a point on a second length of wire which latter point lies at said intersection, all of said wire lengths being connected in series, said circuit including a transhaving an intermediate potential relative to those potentials of said two taps.

18. In apparatus as set forth in claim 17, said transformer having two secondary windings and said wire lengths being connected in a series loop circuit with said windings.

References Cited UNITED STATES PATENTS 2,948,999 8/1960 Schlayer et a1. 53-183 X 3,364,650 1/1968 House 53-182 3,112,586 12/1963 Luetzow 53-29 TRAVIS S. MCGEHEE, Primary Examiner E. F. DESMOND, Assistant Examiner v US. 01. X.R. 156-583; 219-243 

